Dunkin’ Donuts has unveiled a promotion that could mean free coffee for a year. FILE(Staff Writer)

For the fourth year, Dunkin’ Donuts is teaming up with the Cincinnati Bengals for a “Who Dey, Win Day” promotion this season that gives customers a free cup of coffee the day after a Bengals win — if they do a little advance work.

The offer is good for a medium hot or iced coffee for customers who have downloaded the Dunkin’ Donuts app on their cell phones. Each day that follows a Bengals win, the Dunkin’ Mobile App will send customers a coupon they can redeem for the free coffee, according to a Dunkin’ Donuts release.